Fine-grained metallic coatings having the coefficient of thermal expansion matched to the one of the substrate

ABSTRACT

Fine-grained (average grain size 1 nm to 1,000 nm) metallic coatings optionally containing solid particulates dispersed therein are disclosed. The fine-grained metallic materials are significantly harder and stronger than conventional coatings of the same chemical composition due to Hall-Petch strengthening and have low linear coefficients of thermal expansion (CTEs). The invention provides means for matching the CTE of the fine-grained metallic coating to the one of the substrate by adjusting the composition of the alloy and/or by varying the chemistry and volume fraction of particulates embedded in the coating. The fine-grained metallic coatings are particularly suited for strong and lightweight articles, precision molds, sporting goods, automotive parts and components exposed to thermal cycling. The low CTEs and the ability to match the CTEs of the fine-grained metallic coatings with the CTEs of the substrate minimize dimensional changes during thermal cycling and prevent premature failure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No.11/013,456, filed Dec. 17, 2004.

1. FIELD OF THE INVENTION

This invention relates to fine-grained (average grain-size: 1-1,000 nm)metallic coatings optionally containing particulates to form metalmatrix composites (MMCs). The fine-grained metallic materials have a lowcoefficient of thermal expansion, exhibit high strength, high wearresistance, high modulus of resilience and high corrosion resistance.Reducing the grain size strongly enhances selected physical propertiesof the coating e.g. in the case of nickel, the ultimate tensile strengthincreases from 400 MPa (for conventional grain-sizes greater than 5micron) to 1,000 MPa (grain size of 100 nm) and ultimately to over 2,000MPa (grain size 10 nm). Similarly, the hardness for nickel increasesfrom 140 HV (for conventional grain-sizes greater than 5 micron) to 300HV (grain size of 100 nm) and ultimately to 650 HV (grain size 10 nm).The wear rate for dry pin-on-disc decreases from 1,330 μm³/μm forconventional nickel to 7.9 μm³/μm for nickel with a grain size of 10 nm.

Suitable permanent substrates include metals and metal alloys, glass,ceramics, composites and carbon based materials selected from the groupof graphite, graphite fibers and carbon nanotubes as well as polymermaterials filled with or reinforced with e.g. graphite or glass toreduce the CTE. For strength and cost reasons, filled polymers are verydesirable plastic substrate materials for automotive applications. Theterm “filled” as used herein refers to polymer resins which containfillers embedded in the polymer, e.g. fibers made of graphite, carbonnanotubes, glass and metals; powdered mineral fillers (i.e., averageparticle size 0.2-20 microns) such as talc, calcium silicate, silica,calcium carbonate, alumina, titanium oxide, ferrite, and mixedsilicates. A large variety of filled polymers having a filler content ofup to about forty percent by weight are commercially available from avariety of sources. If required, e.g. in the case of electricallynon-conductive or poorly conductive substrates and the use ofelectroplating for the coating deposition, the substrates can bemetallized to render them sufficiently conductive for plating. Thefine-grained coating layer is substantially thicker than the metallizedlayer. The composition of the fine-grained metallic coating is selectedto match the CTE of the electrodeposited metallic material with the oneof the permanent substrate as outlined in Table 1. TABLE 1 Coefficientsof Thermal Expansion Ranges for Selected Substrate Materials andFine-Grained Coatings Coefficient of Thermal Expansion @ RT Fine-grainedCoatings (metal/metal [10⁻⁶ K⁻¹] alloy grain-size ≦1,000 nm) Substrate−1 to 5 NiCo-60-70Fe; W/W Alloys; fine-grained Aerospace and CommercialGraphite MMCs Composites, Pyrex glass  5-10 Mo/Mo Alloys; Zr/Zr Alloys;V/V Alloys; Fiberglass Composites; Epoxy/Kevlar Pt/Pt Alloys,NiCo-40-60Fe, NiCo-70- Composites, glass 100Fe; fine-grained MMCs 10-15NiCo-0-40Fe, Ni/Ni Alloys, Co/Co Glass filled Polyimide; glass filledEpoxy; Ti/Ti Alloys; Ti/Ti Alloys; Au/Au Alloys; fine- alloys, Fe andSelected Steels grained MMCs 15-20 Cu/Cu Alloys; fine-grained MMCs Ni/NiAlloys; Co/Co Alloys, Cu/Cu Alloys, Mild (15) and Stainless Steels (19),Sn/Sn Alloys (20) 21-25 Al Alloys; fine-grained MMCs Al/Al alloys (6061T-6) (23); glass filled polycarbonate (22), glass filled Nylon (23),glass filled polyester (25), Zytel containing short glass fibers(22) >25 — Zn/Zn Alloys, Mg/Mg alloys, Pb/Pb alloys, unfilled polymersincluding Epoxy, PVC, Polycarbonate, Acrylic, ABS, Nylon, Polypropylene,Polyethylene

The fine-grained metallic coatings are deposited onto permanentsubstrates using several known deposition processes includingelectrodeposition, physical vapor deposition (PVD), chemical vapordeposition (CVD), gas condensation, cold spraying and the like. Theseprocesses economically and conveniently enable the deposition of thecoating and to achieve the desired coating properties and CTEs.

Suitable articles include, but are not limited to, precision graphitefiber/epoxy molds used in aerospace, automotive and other industrialapplications that are exposed to repeated temperature cycling (between200 K and up to 623 K). Laminate parts made from the fine-grainedmetallic coatings on appropriate substrates are well suited for highprecision molding components requiring great dimensional stability overa wide operating temperature range. Products of the invention also finduse e.g. in automotive, aerospace, electronic and sporting goodsapplications. Strong, ductile, lightweight, wear and corrosion resistantfine-grained coatings of low internal stress and low friction withexcellent heat conductivity are deposited onto suitable substrates. Thecoefficient of thermal expansion between the coating and the permanentsubstrate can be closely matched to prevent premature failure e.g. byblistering, delamination or cracking during repeated temperature cyclingwithin the operating temperature range of interest (73 K to 873 K).

A variety of fine-grained metallic coatings, which at room temperaturehave a coefficient of thermal expansion in the range between−5.0×10⁻⁶K⁻¹ and 25×10⁻⁶K⁻¹, can be employed. Particularly suited arefine-grained high-strength pure metals or alloys containing one of Al,Cu, Co, Ni, Fe, Mo, Pt, Ti, W and Zr; alloys containing at least twoelements selected from Al, Cu, Co, Ni, Fe, Mo, Pt, Ti, W and Zr; puremetals or alloys of Al, Cu, Co, Ni, Fe, Mo, Pt, W and Zr, furthercontaining at least one element selected from Ag, Au, B, C, Cr, Mo, Mn,P, S, Si, Pb, Pd, Rh, Ru, Sn, V and Zn; and optionally containingparticulate additions such as metal powders, metal alloy powders andmetal oxide powders of Ag, Al, Co, Cu, In, Mg, Mo, Ni, Si, Sn, Pt, Ti,V, W, Zn; nitrides of Al, B and Si; C (graphite, carbon fibers, carbonnanotubes or diamond); carbides of B, Cr, Bi, Si, W; ceramics, glassesand polymer materials such as polytetrafluoroethylene (PTFE),polyvinylchloride (PVC), acrylonitrile-butadiene-styrene (ABS),polyethylene (PE), polypropylene (PP). The particulate average particlesize is typically between 500 nm and 5 μm. The composition of thefine-grained metallic material as well as the volume fraction andchemistry of the particulate additions are chosen to achieve the CTEvalue desired for matching the coating CTEs to the CTEs of the substrateand to achieve the desired coating properties. It is understood in thiscontext that matching of the substrate and fine-grained metallic coatingCTEs does not necessarily mean that the respective CTEs are identicalbut that the “relative mismatch” between the CTE of the fine-grainedmetallic material and the CTE of the permanent substrate is minimized tothe extent required to provide the desired thermal cycling durabilityfor the particular application. The tolerable “CTE mismatch” depends onthe application, the maximum and minimum operating temperature and thenumber of temperature cycles the article is required to withstand in itsoperating life. In addition, mechanical and chemical properties requiredin the specific application need to be taken into consideration as well.In all instances, after a predetermined number of thermal cycles,consisting either of submersing the article in liquid nitrogen for oneminute followed by submersion in hot water for one minute, or theANSI/ASTM specification B604-75 section 5.4 Thermal Cycling Test, thecoating relative to the underlying substrate is displaced by less than2% and no delamination takes place. The fine-grained coating furthermoredoes not blister or crack which would compromise the appearance orperformance of the article.

2. DESCRIPTION OF PRIOR ART/BACKGROUND OF THE INVENTION

Carbon fiber precision composite tools, molds and dies are commonly usedin industry, e.g. for fabricating carbon fiber reinforced compositeprototypes in the aerospace industry. Various iron-nickel alloys(Invar®, Nilo®) have a low coefficient of thermal expansion (CTE) andare used in bulk form for molds and tooling for fabricating precisioncomposite parts. Composite parts are made e.g. by building layers ofcarbon cloth fibers impregnated with resin on suitable tools or molds,followed by curing in an autoclave at around 450 K (thermoset epoxyparts) or up to 725 K (thermoplastic resins). After curing the compositepart is removed from the tool and the process is repeated.

Carbon fiber composite mold tooling is relatively cheap, easy tofabricate and machine; however, it is not very durable and thus is onlysuitable for prototypes or limited production runs. Metallic molds e.g.made of Invar® or Nilo® provide increased strength and wear resistanceand higher durability but are expensive. Metallic coatings can beapplied to mold/tooling substrates made from carbon composites orpolymeric materials, however, the close matching of the thermalexpansion coefficient of the coating layer and the substrate limits theselection of metals to Invar® and Nilo® type alloys which do not possessthe required mechanical strength and wear resistance to obtain thedesired durability and service life, when applied as coatings versusbulk form

In molding applications (blow, injection, compression molding and thelike), for instance, it is desirable that the coefficient of thermalexpansion (CTE) of the mold be it bulk metal or metal coating is closelymatched to that of non-metallic (e.g. carbon fiber) composite componentto avoid spring-back during heating and cooling due to CTE mismatch.

Various patents address the fabrication of molds/tooling using low CTEInvar (Ni-65% Fe alloy) to minimize material scrap generated and toreduce cost as compared to machining the die out of a metal block:

Kenney in U.S. Pat. No. 6,672,125 (2004) discloses a method forfabricating Invar based tooling by super plastically forming a tool froma planar Invar face sheet using a die with the predetermined contour.The diaphragm is heated to the super plastic temperature and pressure isapplied to cause the Invar face sheet to form against the contour of thedie. Super plastically forming the Invar face sheet results in anegligible amount of scrap compared to machining molds from a block andreduces the material and labor costs.

Covino in U.S. Pat. No. 5,817,267 (1998) discloses a method forfabricating a mold by providing a matrix having a shape to be molded,and spraying molten metal from a spray gun. Metals selected from thegroup of Fe, Ni, Zn, Al and Cu are deposited on the matrix, forming ashell, which is removed from the matrix and used as a mold. The processdescribed reduces the cost of mold making when compared to machininglarge molds from solid blocks of particularly nickel alloys, containing36-50% nickel, having a low coefficient of thermal expansion. As thethermal spray process used involves melting followed by resolidificationthe resulting coating is coarse grained.

Oyama in U.S. Pat. No. 5,453,173 (1995) discloses a three-dimensionalelectroformed shell for a mold consisting of a three-dimensionalthin-walled body and an electroformed coating deposited on it. A processfor manufacturing the shell is also disclosed. If the network body ismade of a non-conductive material, electric conductivity is imparted tothe surface e.g. by applying a conductive paint, electroless plating,vacuum evaporation or sputtering. The network body is coated with nickelusing electrodeposition.

Carson in U.S. Pat. No. 3,867,264 (1975) discloses an electroformingprocess for replicating the surface contour of a master form. Apre-plate solution is coated on the form and comprises a combination ofa metal compound capable of being reduced to its active metalconstituent so as to form catalytic bonding sites for a further metalplating process, binder material comprising one or more polymer and/orpolymer formers, and at least one solvent for the binder material andthe metal compound. The binder material is chosen to provide a polymericsubstance having poor adhesion for the form surface. The binder is driedto a polymer layer on the form and thereafter a conductive metal layeris electrolessly plated on the polymer layer. Subsequently, copper ornickel are electroplated onto the conductive layer to a desiredthickness of at least 0.5 mil (12.5 μm), which is substantially greaterthan the thickness of the electrolessly-plated layer. In the final stepthe electroplated metal is removed from the form.

Various patents address the fabrication of sporting goods containing ametallic coating on a polymer substrate, particularly carbonfiber/epoxies:

Yanagioka in U.S. Pat. No. 4,188,032 (1980) discloses a nickel-platedgolf club shaft made of fiber-reinforced material having onsubstantially its entire outer surface a metallic plating selected fromthe group consisting of nickel and nickel based alloys for the purposeof providing a wear-resistant coating. The electroless nickel coating ofchoice is 20 μm thick and the deposition time is 20 hrs, resulting in adeposition rate of 1 μm/hr.

Reed in U.S. Pat. No. 5,655,981 (1997) describes a shaft for a hockeystick comprising a non-metallic elongated material member; a first layercomprised of a resilient yet tough material bonded to the member; asecond layer comprised of metal applied to the first layer by a metaldeposition process; and a third layer comprised of a clear, resilient,tough material encasing said second layer of metal. The thin metalliclayer is applied to the substrate by a vapor vacuum deposition process.The base layer, metallic layer and top layer have an overall thicknessof less than about 3 mils. The purpose of the thin metallic layerapplied to a non-metallic shaft, having a maximum thickness of 0.01 mil(0.25 elm), is entirely to enhance the appearance and the metals ofchoice include aluminum, copper, gold and silver.

Various patents address the fabrication of articles for a variety ofapplications:

Palumbo in U.S. Ser. No. 11/013,456 (2004), assigned to the sameapplicant, discloses articles for automotive, aerospace, manufacturingand defense industry applications including shafts or tubes used, forexample, as golf club shafts, ski and hiking poles, fishing rods orbicycle frames, skate blades and snowboards that are at least partiallyelectroplated with fine-grained layers of selected metallic materialsusing aqueous electrolytes. The articles are strong, ductile andlightweight and exhibit a high coefficient of restitution and a highstiffness. Suitable substrates to be coated include metallic andnon-metallic materials. Suitable metal substrates include aluminum,titanium, steel, stainless steel, copper, brass, bronze, zinc,magnesium, tin and nickel, or their alloys. Non-metallic substratesinclude polymeric resin matrix composites employing materials includingcarbon fibers, ceramic matrix, aramid fibers, polyethylene fibers,boron, fiberglass, and various thermoplastics including, but not limitedto, polypropylene, polyethylene, polystyrene, vinyls, acrylics, nylonand polycarbonates, among others.

Aldissi in U.S. Pat. No. 5,218,171 (1993) describes a method offabricating wires and cables of low weight specifically for aerospaceapplications by silver coating an aramid fiber core to provide cableshaving about half the weight and about 15 times the tensile strength ofcables having equivalent resistance and/or equivalently sized cores ofsilver plated copper. The metal coating is applied in two steps, namelyby (1) electroless plating a high tensile strength fiber comprisingnylon, aramid, etc., with a layer of a metal such as copper, silver;followed by (2) electroplating a second metal layer.

Burgess in U.S. Pat. No. 3,749,021 (1973) discloses a metal-platedplastic cartridge casing. A nickel or chromium metal film, preferablybetween 0.05 to 0.1 mils thick is plated onto a plastic cartridge caseto increase the strength, abrasion and burn-through resistance as wellas lubricity of the cartridge casing. The plastic casing may comprise afilled or a fiber reinforced plastic. A plated metal skin preferably 5to 7 mils thick may also be employed in conjunction with non-reinforcedplastic casings to increase the strength of the casing in selectedareas.

Various patents disclose electroplating processes for the preparation ofmetallic coatings including Ni—Fe alloy coatings:

Tremmel in U.S. Pat. No. 3,974,044 (1976) discloses an aqueousnickel-iron alloy plating bath containing nickel ions and iron ions, asoluble non-reducing complexing agent, and a reducing saccharideselected from the group consisting of monosaccharides and disaccharides.The combination of hydroxy carboxylic acid complexers and reducingsaccharide in such baths yielding high iron content bright levelnickel-iron alloy deposits containing up to 50 percent iron, whileretaining the Fe+³ concentration in the bath at a minimum value andreducing the amount of complexing agents required. Generally, it ispreferred to utilize from about 1 to about 50 grams per liter of areducing saccharide and from about 2 to about 100 grams per liter of thecomplexing agent.

Luch in U.S. Pat. No. 4,195,117 (1980) discloses the use of nickel-ironalloy strike deposits on directly plateable plastics and plated objectssuitable for severe and very severe service conditions according toANSI/ASTM specification B604-75.

Erb in U.S. Pat. No. 5,352,266 (1994), and U.S. Pat. No. 5,433,797(1995), assigned to the same applicant, describe a process for producingnanocrystalline materials, particularly nanocrystalline nickel. Thenanocrystalline material is electrodeposited onto the cathode in anaqueous acidic electrolytic cell by application of a pulsed current. Thecell also optionally contains stress relievers. Products of theinvention include wear resistant coatings, magnetic materials andcatalysts for hydrogen evolution.

Palumbo DE 10,288,323 (2005), assigned to the same applicant, disclosesa process for forming coatings or freestanding deposits ofnanocrystalline metals, metal alloys or metal matrix composites. Theprocess employs tank, drum plating or selective plating processes usingaqueous electrolytes and optionally a non-stationary anode or cathode.Novel nanocrystalline metal matrix composites are disclosed as well.

Park in WO04094699A1 (2004) discloses a process for producing nano Ni—Fealloys with a Ni content in a range of 33 to 42 wt % by electroplating,specifically a nanocrystalline Invar alloy having a grain size of 5 to15 nm. The aqueous electrolyte comprises, on the basis of 1 liter ofwater, 32 to 53 g of ferrous sulfate or ferrous chloride, a mixturethereof; 97 g of nickel sulfate, nickel chloride, nickel sulfamate or amixture thereof; 20 to 30 g of boric acid; 1 to 3 g of sodium saccharin;0.1 to 0.3 g of sodium lauryl sulfate; and 20 to 40 g of sodiumchloride. The Fe—Ni alloys exhibit excellent mechanical propertiescompared to the conventional polycrystalline Fe—Ni alloy and a negativecoefficient of thermal expansion.

Park in WO04074550A1 (2004) discloses an aqueous electrolyte for thepreparation of nanocrystalline Ni—Fe alloys having a coefficient ofthermal expansion of not more than 9×10⁻⁶K⁻¹ by electrodeposition. Theaqueous electrolyte comprises, on the basis of 1 liter of water, 25 to73 kg of ferrous sulfate or ferrous chloride or a mixture thereof, 97 gof nickel sulfate or nickel chloride or nickel sulfamate or a mixturethereof, 20 to 30 g of boric acid, 1 to 3 g of sodium saccharin, 0.1 to0.3 g of sodium lauryl sulfate, and 20 to 40 g of sodium chloride. TheNi content of the Fe—Ni alloy produced using said electrolyte lies inthe range of 20% to 50 wt %.

Bukowski in DE 10108893A1 (2002) describes the galvanic synthesis offine-grained (group II to V or the transition elements) metals, theiralloys and their semiconductors compounds using ionic liquid or moltensalt electrolytes.

Various patents disclose low temperature powder spray processes for thepreparation of metallic coatings:

Alkhimov in U.S. Pat. No. 5,302,414 (1991) describes a cold gas-dynamicspraying method for applying a coating to an article by introducingmetal or metal alloy powders, polymer powders or mechanical mixturethereof with a particle size ranging from about 1 to about 50 micronsinto a gas stream. The gas and particles form a supersonic jet having avelocity of from about 300 to about 1,200 m/sec and a temperatureconsiderably below the fusing temperature of the powder material. Thejet is directed against an article of a metal, alloy or dielectric,thereby coating the article with the particles.

Tapphorn in U.S. Pat. No. 6,915,964 (2005) describes a process forforming coatings by solid-state deposition and consolidation of powderparticles entrained in a subsonic or sonic gas jet onto the surface ofan object. Under high velocity impact and thermal plastic deformation,the powder particles adhesively bond to the substrate and cohesivelybond together to form consolidated materials with metallurgical bonds.The powder particles and optionally the surface of the object are heatedto a temperature that reduces yield strength and permits plasticdeformation at low flow stress levels during high velocity impact, butwhich is not so high as to melt the powder particles.

3. SUMMARY

This invention focuses on enhancing the mechanical strength and wearproperties of fine-grained metallic coatings with an average grain sizebetween 1 and 1,000 nm and metal matrix composite coatings exhibiting acoefficient of thermal expansion (CTE) in the range of −5×10⁻⁶K⁻¹ to25×10⁻⁶K⁻¹ at room temperature as e.g. indicated in Table 1 by grainrefinement (Hall Petch Strengthening) and optionally by addingparticulates to the coating. Metal matrix composites (MMCs) in thiscontext are defined as particulate matter embedded in a fine-grainedmetal matrix. MMCs can be produced e.g. in the case of using anelectroplating process by suspending particles in a suitable platingbath and incorporating particulate matter into the electrodeposit byinclusion or e.g. in the case of cold spraying by adding non-deformableparticulates to the powder feed.

It is an objective of this invention to maintain the room temperatureCTE of the fine-grained metallic coating as well as the room temperatureCTE of the substrate in the range of −5×10⁻⁶K⁻¹ to 25×10⁻⁶K⁻¹,preferably in the range of −1×10⁻⁶K⁻¹ to 15×10⁻⁶K⁻¹ to enhance thethermal cycling performance of the article.

It is an objective of this invention to provide articles composed offine-grained metallic coatings on substrates and multi-layer laminatescomposed of alternating layers of fine-grained coatings and substratescapable of withstanding 1, preferably 5, more preferably 10, morepreferably 20 and even more preferably 30 temperature cycles betweenliquid nitrogen (T=˜−196° C. for one minute) and hot water (T=˜90° C.for one minute) without delamination and with a displacement of thecoating relative to the underlying substrate of under 2%, preferablyunder 1% and even more preferably under 0.5%.

It is an objective of this invention to provide articles composed offine-grained metallic coatings on substrates capable of withstanding 1,preferably 5, more preferably 10, more preferably 20 and even morepreferably 30 temperature cycles without failure according to ANSI/ASTMspecification B604-75 section 5.4 (Standard Recommended Practice forThermal Cycling Test for Evaluation of Electroplated Plastics ASTMB553-71) for service condition 1, preferably service condition 2,preferably service condition 3 and even more preferably for servicecondition 4.

It is an objective of this invention to provide a means for matching ofthe CTE of the fine-grained metallic coating to the CTE of the substrateby adjusting the composition of the alloy and/or by varying thechemistry and volume fraction of particulates embedded in the metalliccoating.

It is an objective of this invention to provide a fine-grained metalliccoating containing elements selected from the group of Al, Cu, Co, Ni,Fe, Mo, Pt, Ti, W, Zn and Zr.

It is a further objective of this invention to provide fine-grainedcoatings composed of Fe alloyed with Co and/or Ni, having a minimum ironcontent of 5%; or 10%, a maximum iron content of 75%; 90% or 95%, aminimum combined nickel/cobalt content of 2.5%; 5% or 10% and a maximumcombined nickel/cobalt content of 80%; 90% or 95%.

It is an objective of the invention to deposit 30 micron to 5 cm thick,fine-grained metal, metal alloy or metal matrix composite coatings andenhance at least one property selected from the group of strength,hardness, friction, scratch and wear resistance compared tocoarse-grained coatings of the same composition. Metal matrix compositesconsist of fine-grained pure metals or alloys with suitable particulateadditives such as powders, fibers, nanotubes, flakes, metal powders,metal alloy powders and metal oxide powders of Al, Co, Cu, In, Mg, Ni,Si, Sn, V, and Zn; nitrides of Al, B and Si; C (graphite, diamond,nanotubes, Buckminster Fullerenes); carbides of B, Cr, Bi, Si, W; andself lubricating materials such as MoS₂ or organic materials e.g. PTFE.

It is an objective of the invention to deposit fine grained-metallicmaterials onto a substrate by a process selected from electrodeposition,physical vapor deposition (PVD), chemical vapor deposition (CVD), gascondensation and cold spraying techniques.

It is an objective of the invention to use metallic and non-metallicsubstrates e.g. as indicated in Table 1 exhibiting a coefficient ofthermal expansion (CTE) in the range of −5×10⁻⁶K⁻¹ to 25×10⁻⁶K⁻¹,preferably in the range of −1×10⁻⁶K⁻¹ to 15×10⁻⁶K⁻¹ at room temperature.Examples of suitable metallic substrates are coarse-grained andfine-grained metals and alloys of Al, Cu, Co, Ni, Fe, Mo, Pt, Ti, W andZr. Examples of suitable non-metallic substrates are glass, polymericresin composites or other filled polymeric materials including, but notlimited to, ABS, polypropylene, polyethylene, polystyrene, vinyls,acrylics, nylon and polycarbonates with a CTE of no more than 25×10⁻⁶K⁻¹at room temperature. Suitable fillers include carbon, ceramics, oxides,carbides, nitrides, polyethylene, fiberglass and glass in suitable formsincluding fibers and powders.

It is an objective of the invention to apply the fine-grained metalliccoating to at least a portion of the surface of a part madesubstantially of glass fiber composites or carbon/graphite fibercomposites including carbon fiber/epoxy composites, optionally aftermetallizing the surface (layer thickness ≦10 micron, preferably ≦1micron) with a thin layer of nickel, copper, silver or the like for thepurpose of enhancing the electrical conductivity of the substratesurface. The fine-grained coating is always substantially thicker (≧25micron) than the metallized layer.

It is an objective of this invention to at least partially coat complexshapes with a metallic layer that is strong, stiff, lightweight andexhibits ductility in the range of 1-20%.

It is an objective of this invention to provide lightweight molds, moldcomponents or tooling parts with increased strength, stiffness,durability, wear resistance, thermal conductivity and a low coefficientof thermal expansion.

It is an objective of this invention to deposit e.g. usingelectroplating, PVD, CVD or powder coating, fine-grained metallicmaterials onto carbon fiber composite substrates requiring little or nomachining after deposition.

It is an objective of the invention to provide articles that are strong,wear and abrasion resistant, light-weight and can be manufactured by aconvenient and cost-effective production process includingelectrodeposition, physical vapor deposition (PVD), chemical vapordeposition (CVD), gas condensation and cold spraying techniques.

It is an objective of this invention to provide articles includingshafts, tubes or other suitable shapes e.g. for use as golf, arrow,hockey, ski or hiking pole shafts, fishing poles, bicycle frames,ammunition casings and other tubular structures e.g. with a circularcross section for use in sporting goods, automotive and industrialcomponents and the like that are coated with fine-grained metalliclayers that are lightweight, resistant to abrasion, resistant topermanent deformation, do not splinter when cracked or broken and areable to withstand thermal cycling without degradation.

It is an objective of this invention to at least partially coat theinner or outer surface of parts including complex shapes such asracquets (e.g. for tennis, squash, badminton, etc, baseball/softballbats, skis, golf club face plates and/or heads) or other sportingequipment, automotive components (e.g. grille guards, brackets, runningboards) and industrial components with fine-grained metallic materialsthat are strong, lightweight, have high stiffness (e.g. resistance todeflection and higher natural frequencies of vibration) and are able towithstand thermal cycling without degradation.

It is an objective of the invention to provide golf clubs utilizing agraphite-epoxy/carbon fiber shaft coated with a fine-grained metalliclayer chosen from the group of Ni, Co, Ni—Fe, Co—Fe and Ni—Co—Fe alloysthat are lightweight, capable of achieving increased flight distance,providing improved vibration dampening and increased control over theclub shaft and head by reducing the shaft torque, providing improvedgolf ball flying distance and accuracy characteristics and are able towithstand thermal cycling without degradation.

It is an objective of this invention to provide cables or wires e.g. foruse in aerospace, automotive, sporting goods and other industrialapplications that are lightweight, have a high breaking strength, arecorrosion resistant, capable of withstanding thermal cycling withoutdegradation and are resistant to abrasion and wear by applying afine-grained surface coating with a yield strength of at least 300 MPa,preferably 500 MPa and more preferably over 750 MPa.

It is an objective of this invention to provide cables or wires, whichat a breaking strength similar to conventional wires are more than 5%,preferably more than 10%, more preferably more than 20% and even morepreferably more than 40% lighter than conventional uncoated wires andare able to withstand thermal cycling without degradation.

It is an objective of this invention to provide coated cables or wirescapable of withstanding thermal cycling without degradation, wherein thefine-grained coating represents more than 5%, preferably more than 10%,more preferably more than 20% and even more preferably more than 40% andup to 90% of the of the cross sectional area or the total weight.

It is an objective of this invention to provide polymer-cased ammunitionsuitable for use in repeating firearms with reduced weight compared toconventional brass-cased ammunition.

Accordingly, the invention is directed to an article comprising:

-   -   (a) a permanent substrate which at room temperature has a        coefficient of thermal expansion in the range between        −5.0×10⁻⁶K⁻¹ and 25×10⁻⁶K⁻¹;    -   (b) a fine grained metallic coating on the permanent substrate,        having an average grain size between 2 and 1,000 nm, a thickness        between 25 micron and 5 cm and a coefficient of thermal        expansion in the range between −5.0×10⁻⁶K⁻¹ and 25×10⁻⁶K⁻¹; and    -   (c) said article exhibiting no delamination and the displacement        of the coating relative to the underlying substrate is less than        2% after said article has been exposed to one temperature cycle        consisting of exposure to liquid nitrogen for one minute        followed by exposure to 90° C. hot water for one minute, or one        temperature cycle according to ASTM B553-71 service condition 1,        2, 3 or 4.

The article of the invention can be provided by a process for coatingsurfaces of a work piece after suitable surface preparation e.g. bysanding, grid blasting and/or etching, with fine-grained metallicmaterials of high yield strength (300 MPa to 2,750 MPa) and ductility(1-15%) and a low CTE. The term low CTE is used herein to mean no morethan 25×10⁻⁶K⁻¹.

According to one aspect of the present invention an article is providedby a process which comprises the steps of, positioning the metallic ormetallized work piece to be plated in a plating tank containing asuitable electrolyte and a fluid circulation system, providingelectrical connections to the work piece/cathode to be plated and to oneor several anodes and plating a structural layer of metallic materialwith an average grain size of less than 1,000 nm on the surface of themetallic or metallized work piece using suitable direct current (D.C.)or pulse electrodeposition processes described e.g. in the copendingapplication U.S. Ser. No. 10/516,300 (2004) (DE 10,288,323).

Articles of the invention comprise fine-grained coatings having low CTEsat high deposition rates, having a thickness of at least 0.025 mm,preferably more than 0.030 mm, more preferably more than 0.050 mm andeven more preferably more that 0.100 mm deposited on substrates ofmatching CTEs including industrial products (e.g. molds), automotiveproducts (e.g. running boards, grill guards), military products (e.g.ammunition, armor), sporting goods (e.g. golf club heads, inserts forgolf club heads, face plates for golf clubs, shafts for golf clubs,arrows, hiking and skiing poles, walking sticks, lacrosse sticks).

Articles of the invention comprise a single or several fine-grainedmetallic layers applied to the substrate as well as multi-layerlaminates composed of alternating layers of fine-grained metallic layersand substrates.

The fine-grained metallic coatings have a grain size under 1 μm (10,000nm), preferably in the range of 5 to 500 nm, more preferably between 10and 100 nm.

The fine-grained coatings have a modulus of resilience of at least 0.25MPa, preferably at least 1 MPa, more preferably at least 2 MPa, morepreferably at least 5 MPa and even more preferably at least 7 MPa.

In a preferred embodiment article of this invention, e.g., involving Pcontaining coatings, the coatings are dispersion strengthened by asubsequent heat-treatment.

According to this invention, the entire article can be coated,alternatively patches or sections can be formed on selected areas only(e.g. golf club face plates or sections of golf club shafts, arrows orpolymer cartridge casings), without the need to coat the entire article.

According to this invention patches or sleeves which are not necessarilyuniform in thickness can be deposited in order to e.g. enable a thickercoating on selected sections or sections particularly prone to heavy usesuch as golf club face or sole plates, the tip end of fishing poles,arrows and shafts for golf clubs, skiing or hiking poles, polymercartridge casings and the like.

According to this invention fine-grained metal coated carbon-fibercomposite molds and their components with low thermal expansioncharacteristics can be formed. Carbon fiber composite molds are popularfor fabricating composite prototypes for the aerospace industry. Whilecarbon-fiber molds are cheap, they are, however, not very durable andfind use only for prototyping. Depositing fine-grained metals such asNi—Fe alloys directly onto the carbon fiber composite molds provides fortremendous cost savings over the traditional approach of machining andforming Invar molds which are durable enough to be used for productionruns. The fine-grained metal coated carbon-fiber composite molds providean added benefit over traditional Invar molds, namely the high strengthof the fine-grained coating allows for thinner wall thicknesses andreduced overall weight while providing increased durability and wearresistance.

The following listing further defines the article of the invention:

Fine-Grained Coating and Substrate Specification:

Minimum coefficient of thermal expansion [10⁻⁶K⁻¹]: −5.0; −1.0; 0

Maximum coefficient of thermal expansion [10⁻⁶K⁻¹]: 15; 20; 25

Fine-Grained Coating Specification:

Minimum average grain size [nm]: 2; 5; 10

Maximum average grain size [nm]: 100; 500; 1,000

Metallic Layer Thickness Minimum [μm]: 25; 30; 50; 100

Metallic Layer Thickness Maximum [mm]: 5; 50

Minimum Ratio Coating Thickness to Grain Size: 25; 100; 1,000

Maximum Ratio Coating Thickness to Grain Size: 10,000; 100,000;12,500,000

Metallic Materials: Al, Cu, Co, Ni, Fe, Mo, Pt, Ti, W and Zr

Alloying additions: Ag, Au, B, Cr, Mo, P, Pb, Pd, Rh, Ru, Sn, Zn

Particulate additions: metals (Ag, Al, Cu, In, Mg, Si, Sn, Pt, Ti, V, W,Zn); metal oxides (Ag₂O, Al₂O₃, SiO₂, SnO₂, TiO₂, ZnO); carbides of B,Cr, Bi, Si, W; carbon (carbon nanotubes, diamond, graphite, graphitefibers); glass; polymer materials (PTFE, PVC, PE, PP, ABS, epoxy resins)

Minimum Particulate Fraction [% by Volume]: 0; 1; 5; 10

Maximum particulate fraction [% by volume]: 50; 75; 95

Minimum specific tensile strength [kpsi per lb/cu.in]: 25; 50; 100;

Maximum specific tensile strength [kpsi per lb/cu.in]: 250; 500; 750

Minimum Yield Strength Range [MPa]: 300

Maximum Yield Strength Range [MPa]: 2750

Minimum Modulus of Resilience (as defined in U.S. Ser. No. 11/013,456)of the Fine-Grained Metallic Layer [MPa]: 0.25; 1

Maximum Modulus of Resilience of the Fine-Grained Metallic Layer [MPa]:12; 25

Minimum Hardness [VHN]: 100, 200, 400

Maximum Hardness [VHN]: 800, 1000; 2000

Minimum Deposition Rates [mm/hr]: 0.01; 0.05; 0.1; 0.2; 0.5

Substrate Specification:

Metallic Materials: coarse-grained or fine-grained metallic materialsincluding Al, Cu, Co, Ni, Fe, Mo, Pt, Ti, W and Zr with optionalalloying additions of Ag, Au, B, Cr, Mo, P, Pb, Pd, Rh, Ru, Sn, Zn andoptional particulate additions of metals (Ag, Al, Cu, In, Mg, Si, Sn,Pt, Ti, V, W, Zn); metal oxides (Ag₂O, Al₂O₃, SiO₂, SnO₂, TiO₂, ZnO);carbides of B, Cr, Bi, Si, W; carbon (carbon nanotubes, diamond,graphite, graphite fibers); ceramics; lass; polymer materials (PTFE,PVC, PE, PP, ABS, epoxy resins).

Non-Metallic Materials: glass, ceramics, filled polymeric materials andcomposites, carbon based materials selected from the group of graphite,graphite fibers and carbon nanotubes.

Thermal Cycling Performance Specification:

ANSI/ASTM specification B604-75 section 5.4 Test (Standard RecommendedPractice for Thermal Cycling Test for Evaluation of ElectroplatedPlastics ASTM B553-71). The samples are subjected to a thermal cycleprocedure as indicated in Table 2. The sample is held at the hightemperature for an hour, cooled to room temperature and held at roomtemperature for an hour and subsequently cooled to the low temperaturelimit and maintained there for an hour. TABLE 2 Standard RecommendedPractice for Thermal Cycling Test for Evaluation of ElectroplatedPlastics According to ASTM B553-71 Service High Low Condition LimitLimit 1 (mild) 60° C. −30° C. 2 (moderate) 75° C. −30° C. 3 (severe) 85°C. −30° C. 4 (very severe) 85° C. −40° C.

Alternative temperature cycling test: The article is cycled betweenliquid nitrogen (˜196° C. for one minute) and hot water (˜90° C. for oneminute). If any blistering, delamination or cracking is noted the testis immediately suspended. After 10 such test cycles the sample isallowed to cool to room temperature, is carefully checked fordelamination, blistering and cracking and the total displacement of thecoating relative to the substrate is determined.

4. PREFERRED EMBODIMENTS OF THE INVENTION

This invention relies on fine-grained coatings produced, for example, byDC or pulse electrodeposition, physical vapor deposition (PVD), chemicalvapor deposition (CVD), gas condensation and cold spraying techniques.

The person skilled in the art of plating will know how to electroplateselected fine-grained metals, alloys or metal matrix composites choosingsuitable plating bath formulations and plating conditions. Similarly,the person skilled in the art of PVD, CVD, gas condensation and coldspraying techniques will know how to prepare fine-grained metal, alloyor metal matrix composite coatings.

Selecting a suitable substrate and increasing the strength of themetallic coating through grain-size reduction minimizes the overallthickness and weight of articles. Depending on the ductility required agrain size in the range of 10 to 500 nm usually results in a coatingwith suitable mechanical properties. Incorporating a sufficient volumefraction of particulates can further enhance the material properties andreduce the CTE of the coating.

Depending on the requirements of the particular application the materialproperties can also be further altered, e.g., by incorporating solidparticles. Metal matrix composites provide added flexibility to adjustthe CTE and affect mechanical and optionally even functional properties(e.g. lubricants such as MoS₂ and PTFE).

As noted above, particularly suited applications of the fine-grainedlayers disclosed herein include molds, golf shafts, ski poles, fishingrods, arrows and other structures comprised of a conventional metal,plastic or graphite composites that are coated on at least part of theinterior and/or exterior surfaces. Conventional metals e.g. aluminum,copper, nickel and their alloys are relatively soft and permanentlydeform and break easily as a result of the bending loads encounteredduring use. Furthermore these conventional materials exhibit a lowresistance to abrasion and cut or scratch easily and can thereforebenefit greatly from the substantial grain refinement described in thisinvention.

Carbon fiber composites possess much higher rigidity and lower densitythan steel; however, the light-weight, carbon-fiber golf shafts oftenexhibit torque or twisting of the club head relative to the shaft ondown-swing and particularly at ball contact, resulting in poor accuracyand flying distance. This limitation can be overcome by coating at least10% of the composite shaft's external and/or internal surface with thefine-grained metallic layer described.

The solid particles dispersed throughout the fine grained metal layeroptionally include a particulate (e.g. carbon/graphite powder, carbonnanotubes, flakes or fibers, diamond, TiO₂, WC, B₄C) to reduce the CTEand optionally improve hardness, wear resistance and tensile strength.

Suitable non-metallic materials for use as substrates are listed inTable 1 and include resin matrix composites such as carbon fibers,aramid fibers, polyethylene fibers, ceramics, boron, fiberglass, variousreinforced or filled thermoplastics including, but not limited to,polypropylene, polyethylene, polystyrene, vinyls, acrylics, nylon andpolycarbonates, among others.

Electrodeposition is a particularly suited and economic depositionprocess when electrically conductive metal or graphite-containingsubstrates are employed. It will be known to a person skilled in the artthat appropriate surface preparation is required to ensure appropriateadhesion of the coating to the substrate, particularly if the coatingdoes not encapsulate the substrate. If the adhesion of the coating asapplied is already poor at room temperature as can be determined, e.g.by any suitable peel test, the coated article can still fail thermalcycling tests even though the CTEs of the fine-grained coating and thesubstrate are matched as described. Non-conductive or poorly-conductivesubstrates can be rendered suited for electroplating by applying a thinlayer (typically less than 25 μm thick, more typically less than 2 μm)of a conductive material e.g. by electroless deposition of metals suchas Ni, Cu and Ag or applying electrically conductive paints by varioussuitable means. Alternatively, other deposition processes can beemployed to yield fine-grained coatings.

The intermediate conductive layer can comprise a metallic layer or cancomprise polymeric material with conductive particulates therein.

Where the intermediate conductive layer comprises a metallic layer, themetallic layer is constituted of Ag, Ni or Cu or a combination of anytwo or all of these, and the intermediate conductive layer can bedeposited by electroless deposition, sputtering, thermal spraying,chemical vapor deposition, physical vapor deposition of by any two ormore of these.

Where the intermediate conductive layer comprises polymeric materialwith conductive particulates therein, it can be, for example, aconductive paint or a conductive epoxy. The conductive particulates canbe composed of or contain Ag, Ni or Cu or graphite or other conductivecarbon or a combination of two or more of these.

The invention is illustrated by the following working examples.

Example 1 n-Ni Coated Graphite Composite

Penley Graphite Light LS® S-Flex and Penley G2-85® X-Flex graphite/epoxygolf shafts were used (OD₁=0.586″, tapering down to OD₂=0.368″ over alength of 40.5″). The shafts were stripped of the paint, ground withP1000 sandpaper to remove the surface coating and expose the carbonfibers. The surface roughness of the shaft after surface preparation wasdetermined to be Ra˜0.45 micron. The outer surface of the shaft wascoated with various materials to a coating thickness of 50 micron bydepositing fine-grained Ni and NiFe alloys from a modified Watts nickelbath and using a Dynatronix (Dynanet PDPR 20-30-100) pulse power supplyas described in U.S. Ser. No. 11/013,456. The fine-grained coatingrepresented 22% of the total weight of the shaft. Coated samples takenfrom the untapered butt end area were exposed to a thermal cycling testwhich involves submersing about 4-8″ long samples vertically into liquidnitrogen (T=−196° C.) for one minute, immediately followed by submersionin hot water (T=90° C.) for one minute. The sample is inspected fordelamination, blistering, cracks and the like and the relativedisplacement of the coating determined every ten cycles. Thirty suchthermal cycles were performed. In addition, another set of samples wasexposed to 30 thermal cycles according to the ANSI/ASTM specificationB604-75 section 5.4 Thermnal Cycling Test for Service Condition 4(85° C.to −40° C.). The data are displayed in Table 3 and indicate that asignificant reduction in the displacement occurs if the CTEs of thesubstrate and the fine-grained metallic coating are matched. Moreover,all samples passed the liquid nitrogen/hot water cycling test withoutdelamination. Similar results can be obtained when the fine-grainedmetallic coatings are deposited by other processes e.g. by lowtemperature spraying of powders resulting in a coating with a grain sizein the 1 to 1,000 nm range. In all cases it was found that the degree ofdisplacement can be reduced by reducing the differences in CTEs betweenthe fine-grained coating and the substrate. TABLE 3 Thermal Cycling TestResults Thermal Cycling Test ANSI/ASTM Coating (−196 to 90° C.)specification Substrate Coating Grain Performance after B604-75 section5.4 Substrate CTE Coating CTE Size 30 cycles/Displacement ThermalCycling Chemistry [10⁻⁶ K⁻¹] Chemistry [10⁻⁶ K⁻¹] [nm]

L/L [%] Test/SC4; 30 cycles Graphite/Epoxy 3.5 100Ni—0Fe 13 20 Pass/0.45Pass Composite Graphite/Epoxy 3.5 80Ni—20Fe 10.8 15 Pass/0.46 PassComposite Graphite/Epoxy 3.5 38Ni—62Fe 2.5 15 Pass/0.15 Pass Composite

To investigate the effect of increasing metal content, hybridgraphite/metal golf shafts were prepared with the weight of the finegrained coating representing between 10 and 90% of the total weight ofthe shaft. The torsional stiffness per unit weight of the shaftscontaining the fine-grained metallic coating improved by at least about5% when compared to the torsional stiffness of the same article notcontaining the metallic coating. The torque and deflection data indicatethat a significant performance improvement can be obtained by increasingthe relative metal weight of the composite graphite/metal shafts.Graphite/metal composite golf shafts incorporating a metallic coatingrepresenting at least 5%, preferably more than 10% and even morepreferably more than 20% of the total weight provide a substantialimprovement over the performance of uncoated graphite shafts. Selectedcoated shaft samples were exposed to both thermal cycling testsdescribed above. The data indicated that matching the CTEs of thefine-grained metallic coating to the graphite-epoxy substrate providedacceptable thermal cycling performance, no delamination occurred and therelative displacement between the coating and the substrate was lessthan 0.75% in all cases.

Example 2 Arrow Shafts; NiFe on Graphite/Epoxy

Over time archery arrows progressed from being made out of wood toaluminum. Aluminum arrows are about 25% lighter than cedar wood arrowsbut with repeated use aluminum arrows tend to bend causing inconsistenttrajectories and loss in accuracy. More recently graphite-compositearrows appeared. Those being made from carbon fibers/polyvinyl orpolyester resins. Graphite-composite arrows are lighter and tougher thanaluminum and they do not bend when striking a hard object. The lighterweight also leads to increased speed resulting in delivering higherkinetic energy on impacting the target. State of the art graphitecomposite arrows, however, also have a number of limitations. They tendto oscillate along the shaft, causing inaccuracies in flight and reducedpenetration after hitting game. Due to the relatively limited “spineweight” and their low stiffness it is difficult to use them with bowswith more than 50 lb draw weight. Furthermore, upon penetrating thetarget the friction generated heats up the tip section of the shaft to atemperature of over 150 to 200° C., which is significantly above themaximum temperature the graphite fiber/epoxy composite is able towithstand, resulting in degradation of the graphite fiber/epoxycomposite shaft, deterioration of its performance and ultimately failureof the shaft. To improve the shaft thermal cycling performance andreduce the impact damage in the tip section 30″ carbon-epoxy/fiberglasstest shafts were reinforced with an outer layer (thickness: 0.004″) of afine-grained Ni-20Fe alloy in the tip section. The fine-grainedreinforcement layers extended part of the way (e.g. 4″) or all the wayup the length of the base shaft making the shaft more resistant toimpacts. The enhanced thermal conductivity distributes the heat offriction generated upon impacting the target over a much larger surfacethereby reducing the maximum temperature the graphite fiber/epoxycomposite is exposed to and thus durability is increased. The same basicdeposition procedure as described in U.S. Ser. No. 10/516,300 for amodified Watt's bath for NiFe was followed for coating all the arrowshafts with a fine-grained Ni-20Fe material with an average grain sizeof 20 nm. After the portion of the shaft to be plated was abraded andmetallized by a chemical silver spray, a fine-grained Ni-20Fe layer wasplated onto the outside surface. Test samples were prepared with thefine-grained Ni-20Fe coating representing between 1 and 50% of the totalarrow weight. The shafts were fitted with field tips, nocks and suitablevanes and submitted to tests using a compound bow with a draw weight of60 lb. Overall the arrows containing the fine-grained metallic coatingconsistently outperformed the uncoated arrows. Samples with afine-grained metal layer of at least 5% of the total weight of the arrowdisplayed a performance superior to that of conventional graphitefiber/epoxy and aluminum arrow shafts. Reinforcing the arrow shaft inthe tip section (2″ to 8″) with a 0.001″-0.008″ thick fine-grainedcoating proved particularly beneficial. Selected coated shaft sampleswere exposed to the thermal cycling tests described in Example 1. Thedata displayed in Table 4 indicate that matching the CTEs of thefine-grained metallic coating to the substrate provided acceptablethermal cycling performance. TABLE 4 Thermal Cycling Test ResultsThermal Cycling Test ANSI/ASTM Coating (−196 to 90° C.) specificationSubstrate Coating Grain Performance after B604-75 section 5.4 SubstrateCTE Coating CTE Size 30 cycles/Displacement Thermal Cycling Chemistry[10⁻⁶ K⁻¹] Chemistry [10⁻⁶ K⁻¹] [nm]

L/L [%] Test/SC4; 30 cycles Graphite/Epoxy 5 80Ni—20Fe 11 15 Pass/˜0Pass Composite

Similarly, aluminum arrow shafts were coated with fine-grained aluminum(average grain size 20 nm) according to DE 10108893A1 and exposed tothermal cycling testing. The results confirmed that matching the CTEs ofthe fine-grained metallic coating to the substrate provided acceptablethermal cycling performance.

Example 3 Graphite Molds

2.5×0.75″ coupons of various substrates were suitable pretreated, etchedand coated with various fine-grained materials available from IntegranTechnologies Inc. (www.integran.com) to a coating thickness of 100micron. Substrate materials included graphite/epoxy used for precisionmolds, aluminum and ABS plastic (unfilled) as used, e.g., for sportingequipment and automotive components. After appropriate chemicalactivation, fine-grained NiFe and NiFeCo alloys were deposited from amodified Watts bath as described in U.S. Ser. No. 10/516,300. The coatedsamples were exposed to the harsh thermal cycling test described above.The data displayed in Table 5 indicate that matching the CTEs of thefine-grained metallic coating to the substrate provided acceptablethermal cycling performance. The Ni—Fe coating on the unfilled ABSsubstrate, representing a “CTE mismatch” outside the scope of thisinvention, failed instantly by complete delamination upon insertion ofthe sample into the liquid nitrogen. TABLE 5 Thermal Cycling TestResults Thermal Cycling Test Substrate Coating (−196 to 90° C.) CTE CTEPerformance Substrate Chemistry [10⁻⁶ K⁻¹] Coating Chemistry [10⁻⁶ K⁻¹]after 30 cycles Graphite/Epoxy 1 80Ni—20Fe (20 nm) 11 Pass CompositeGraphite/Epoxy 1 54.3Ni—15.6Co—30.3Fe 11 Pass Composite (20 nm)Graphite/Epoxy 1 60.4Ni—1.1Co—38.5Fe 11 Pass Composite (20 nm)Graphite/Epoxy 1 57.2Ni—1.7Co—41.1Fe 11 Pass Composite (20 nm)Graphite/Epoxy 1 30Ni—70Fe (20 nm) 4 Pass Composite Aluminum 2380Ni—20Fe (20 nm) 11 Pass Aluminum 23 60.4Ni—1.1Co—38.5Fe 11 Pass (20nm) Aluminum 23 30Ni—70Fe (20 nm) 4 Pass ABS, unfilled 74 50Ni—50Fe (20nm) 10 Fail (on 1^(st) cycle by delamination)

Example 4 Ni—P, Co—P on Mild Steel; Faceplate Coating

A mild-steel faceplate insert for a golf club driver head was coatedusing a selective plating unit available from Sifco Selective Plating(www.brushplating.com). Standard substrate cleaning and chemicalactivation procedures provided by Sifco Selective Plating wereperformed. Using the anode brush with manual operation, 125 μm thicknanocrystalline Ni˜0.6 wt % P and Co˜0.8 wt % P layers were depositedonto face plate areas of about 3 in² at a deposition rate of 50 μm/hr.The electrolyte used comprised a modified Watts bath for Ni and Co,respectively, with phosphorous acid and saccharin additions as taught inDE 10,288,323. Selected electroplating conditions and metallic layerproperties used are summarized in Table 6. After plating, the faceplatewas heat-treated as indicated to further enhance the mechanicalproperties by precipitation hardening. No delamination occurred as aconsequence of the heat-treatment in any sample. TABLE 6 CoatingProperties Fine-Grained Coating Ni—0.6P Co—0.8P Average CoatingThickness: [μm] 125 125 Average Grain Size: [nm] 13 12 Ratio CoatingThickness/Grain Size 9,615 10,417 Hardness [VHN] 780 580 Hardness afterHeat Treatment (400° C./20 min) 890 720 [VHN] Hardness after HeatTreatment (400° C./20 min + 1010 — 200° C./11 hrs) [VHN]

As coated samples with and without heat-treatment were exposed to athermal cycling test described in Example 1 involving submersing thesamples into liquid nitrogen (T=−196° C.) for one minute, followed bysubmersion in hot water (T=90° C.) for one minute. Table 7 indicatesthat after 30 thermal cycles no delamination occurred and thedisplacement of the coating relative to the underlying substrate wassubstantially zero in all cases. TABLE 7 Thermal Cycling Test ResultsThermal Cycling Test Coating (−196 to 90° C.) Substrate Coating GrainPerformance after Substrate CTE Coating CTE Size 30 cycles/DisplacementChemistry [10⁻⁶ K⁻¹] Chemistry [10⁻⁶ K⁻¹] [nm]

L/L [%] Mild Steel 15 Ni—0.6P, as plated 11 13 Pass/˜0 Mild Steel 15Ni—0.6P, after HT 11 13 Pass/˜0 (400° C./20 min) Mild Steel 15 Co—0.8P,as plated 11 12 Pass/˜0 Mild Steel 15 Co—0.8P, after HT 11 12 Pass/˜0(400° C./20 min)

Similarly, mild steel faceplates can be coated by cold spraying withfine-grained Ni (average grain size ˜50 nm) according to U.S. Pat. No.5,302,414 using a Ni powder feed (average particle size ˜1 micron,average grain size ˜20 nm) and exposed to thermal cycling testing. Theresults indicated that matching the CTEs of the fine-grained metalliccoating to the substrate provided acceptable thermal cyclingperformance.

Example 5 Co—P-Diamond MMCs

To illustrate the ability to “tailor make” the CTE of fine grainedcoatings, metal matrix composites were prepared as described in DE10,288,323. Specifically, the electrolyte formulation used included 300g/l CoSO₄×7H₂O; 45 g/l CoCl₂×6H₂O; 45 g/l H₃BO₃; 2 g/l Saccharin; 0.1g/l Sodium Lauryl Sulfonate (SLS); 5 g/l Phosphorous Acid; (pH 1.5;Electrolyte temperature: 85° C.; Electrolyte circulation rate: 0.15liter/min/cm² cathode area). To synthesize the metal matrix composite 50g/l of sub-micron sized synthetic diamond particulate (mean particlesize ˜750 nm) was added to bath along with 1 g/l of standard commercialsurfactant. A fine-grained CoP-Diamond composite layer, approximately125 μm thick, was electroformed onto a 4″ length of 0.25″ diameterplastic mandrel (pre-metalized with ˜5 μm of Cu) using a DC current of150 mA/cm2 and a total plating time of 1 hour. 33 vol % of diamondparticulate was incorporated into the fine-grained cobalt-phosphorusmatrix and the resulting effect of these additions on the CTE of thecoating was determined using a quartz dilatometer test method based onASTM standard E228. Table 8 indicates that the CTE of coating can bevaried depending on the choice and amount of the particulate added.TABLE 8 Coefficient of Thermal Expansion of Selected Fine-Grained MetalMatrix Composites Particulate Coating Coating Fine Grained ParticulateAddition Grain Size CTE Coating Chemistry Addition [% Volume] [nm] [10⁻⁶K⁻¹] Co-2 wt % P N/A 0 15 12.9 Co-2 wt % P Diamond 33 15 8.9

Example 6 n-Ni Coated Wire

Ever more demanding performance requirements are being imposed ontotraditional electrical wires and cables in a number of applicationsincluding aerospace applications, where the need for lighter weightwiring is directly related to aircraft performance and operating cost. Anew approach to improve the strength of wires or cables by plating aconventional metal wire with a fine-grained metal, metal alloy ormetal-matrix composite coating is presented here. In a number ofaerospace applications the electrical conductivity required(resistivity: 67Ω/1000 ft) would enable the use of 28 AWG Cu wire (0.48lb/1000 ft); however, as the required nominal breaking strength is over30 lb, 22 AWG wire (1.94 lb/1000 ft) has to be used, significantlyincreasing the weight of the cabling. To demonstrate the benefits ofstrong, fine-grained coatings on the overall performance of Cu wires,fine-grained or coarse-grained Ni coatings were applied to 24 AWG to 28AWG Cu wires by electrodeposition in a modified Watts nickel bath andusing a Dynatronix (Dynanet PDPR 20-30-100) pulse power supply.Electrolyte composition and plating conditions were the same as inExample 1. The plating cell employed was similar to the continuous wireplating cell disclosed in U.S. Pat. No. 5,342,503. The properties of thesamples are summarized in Table 9.

The data presented in Table 9 indicate that the breaking strength of 22AWG Cu wire can be achieved by 24 AWG Cu wire coated with fine-grainedNi (coating volume fraction 23%) with a 18% reduction in weight or by 28AWG Cu wire coated with fine-grained Ni (coating volume fraction 61%)with a 36% reduction in weight. A conventional, coarse-grainedNi-coating based on a commercial Sulfamate Ni plating bath, on the otherhand, provides no benefit; on the contrary, the total weight actuallyincreases in order to match the breaking strength of the conventionalCu-wire. TABLE 9 Sample Wire Property Comparison Coarse- Coarse- Thisgrained grained This invention; Ni Ni invention; Coarse- Coarse- n-Nicoated coated n-Ni grained grained n- Coated 24 Cu 24 Cu 24 Coated 28 Nicoated Ni Coated AWG Cu AWG AWG AWG Cu 28 AWG 28 AWG Wire Wire Wire WireCu Wire Cu Wire Conventional Conventional Conventional (grain (grain(grain (grain (grain (grain 22 AWG Cu 24 AWG Cu 28 AWG Cu size ˜20 size10 size >10 size ˜20 size >10 size >10 Wire Wire Wire nm) μm) μm) nm)μm) μm) Ni Coating 0 0 0 1.43 1.43 3.99 3.79 3.79 6.67 Thickness [mils]Volume Fraction of 0 0 0 23 23 49 61 61 76 the Coating [%] TotalDiameter 25.3 20.1 12.6 23 23 28.1 20.2 20.2 25.9 [mils] Total WireWeight 1.94 1.22 0.48 1.60 1.60 2.39 1.24 1.24 2.04 [lb/1000 ft]Breaking Strength, 34.1 21.7 8.64 34.1 21.7 34.1 34.1 19 34.1 lb WeightSavings at — — — 18 N/A −23 36 N/A −5 Equivalent Breaking strength) [%]Nominal Resistance 16.9 26.7 67.8 ˜26 25.6 ˜65 60 [Ω/1000 ft]

Table 10 illustrates the weight savings achievable on wires and cablesrequiring a breaking strength of 34 lb by applying fine-grained Nicoatings of various thicknesses to conventional Cu wires. TABLE 10Characteristics of Round Copper Wire coated with Fine-Grained Nickel(average grain size 20 nm) Volume fraction Weight Fine-grained Ni fine-Nominal savings over Conductor size Coating grained Ni breaking Netweight, 22 AWG Cu [AWG] thickness [mils] [%] strength [lb] [lb/1000 ft]Wire [%] 22 0 0 34.1 1.940 — 23 0.725 12 34.1 1.755 10% 24 1.43 23 34.11.600 18% 25 2.07 34 34.1 1.473 24% 26 2.69 44 34.1 1.373 29% 27 3.26 5334.1 1.303 33% 28 3.79 61 34.1 1.236 36%

Selected samples of the fine grained Ni coated 24 ASW Cu wires weresubjected to both thermal cycling tests described earlier. In bothcases, 30 thermal cycles were successfully completed without anydelamination and the displacement of the coating relative to theunderlying substrate was substantially zero in all cases.

Alternatively, this example can be carried out by CVD or PVD, e.g.,using a reel-to-reel system.

Example 7 Polymer Cartridges; NiFe on Filled Nylon

Ammunition containing plastic components including polymer cartridgecasings are known but to date have not been produced economically incommercial quantities with acceptable safety and consistent ballisticcharacteristics. Lightweight, polymer-cased ammunition utilizingstandard projectiles, primers, and propellants have the potential tosignificantly reduce the weight of ammunition. Deficiencies encounteredto date include:

-   -   the possibility exists that the projectile can be pushed into        the cartridge casing or fall out;    -   moisture uptake and sealing problems can occur failing to keep        the propellant dry;    -   a poor fit in the chamber can cause problems with inconsistent        projectile accuracy due to the variation in the gas pressure        during firing;    -   during the residence time of the cartridge in the weapon (after        chambering and before firing) the cartridges can be exposed for        some time to high temperatures of up to 200 or even 300° C. e.g.        in automatic weapons which can degrade the polymer;    -   when fired plastic casings can permanently deform or provide        insufficient elastic spring back causing difficulties during        extraction;    -   portions of the polymer cartridge casing can break off or        disintegrate upon firing;    -   problems can be encountered with ease and reliability of spent        polymer cartridge extraction requiring a metal base or a metal        insert;    -   jamming in automatic weapons can occur particularly during        ejection of the casing;    -   insufficient lubricity of the casing fails to ensure reliable        extraction and ejection; and    -   excessive cost can be incurred due to complex designs and        manufacturing processes required.

To demonstrate the performance of composites made of fine-grainedmetallic materials with polymers 5.6 mm (0.223 caliber) polymerammunition casings made of glass-filled Zytel® (CTE: 22×10⁻⁶K⁻¹) wereused and were reinforced by a fine-grained metallic layer. Prior toplating, the outside diameter of the casing to be plated was reduced toaccommodate 0.001″ to 0.010″ thick coatings without changing the outerdiameter. No adjustments were made to the inner diameter of the casingin case the inside surface was plated. The same basic procedure asdescribed in Example 2 was followed for coating all the polymerammunition casings with fine-grained Ni-20Fe with an average grain sizeof 20 nm and a CTE of 11×10⁻⁶K⁻¹. After the portion of the casing to beplated was metallized by silver spraying, a fine-grained Ni-20Fe layerwas plated onto the outside casing from the base to between about halfto the entire overall length. Test samples were prepared with thefine-grained metallic coating representing between 1 and 50% of thetotal casing weight. The casings were fitted with primers, suitablepowder charges and 55 grain FMJ projectiles and submitted to test firingin an M-16 weapon. The performance of the cartridges with respect tochambering, ejecting and accuracy was monitored. Selected samples weresubjected to the two thermal cycling test described. In both cases, 30thermal cycles were successfully completed without any delamination andthe displacement of the coating relative to the underlying substrate wassubstantially zero in all cases.

Variations

The foregoing description of the invention has been presented describingcertain operable and preferred embodiments. It is not intended that theinvention should be so limited since variations and modificationsthereof will be obvious to those skilled in the art, all of which arewithin the spirit and scope of the invention.

1. An article comprising (a) a permanent substrate which at roomtemperature has a coefficient of thermal expansion in the range between−5.0×10⁻⁶K⁻¹ and 25×10⁻⁶K⁻¹; (b) a fine grained metallic coating on thepermanent substrate, having an average grain size between 2 and 1,000nm, a thickness between 25 micron and 5 cm and a coefficient of thermalexpansion in the range between −5.0×10⁻⁶K⁻¹ and 25×10⁻⁶K⁻¹; and (c) saidarticle exhibiting no delamination and the displacement of the coatingrelative to the underlying substrate is less than 2% after said articlehas been exposed to one temperature cycle consisting of exposure toliquid nitrogen for one minute followed by exposure to 90° C. hot waterfor one minute, or one temperature cycle according to ASTM B553-71service condition 1,2, 3 or
 4. 2. An article according to claim 1wherein said fine-grained metallic coating is selected from the groupof: (i) A pure metal selected from the group consisting of Al, Cu, Co,Ni, Fe, Mo, Pt, Ti and Zr, (ii) an alloy containing at least twoelements selected from Al, Cu, Co, Ni, Fe, Mo, Pt, Ti and Zr; (iii) puremetals selected from the group of Al, Cu, Co, Ni, Fe, Mo, Pt, Ti and Zrand alloys containing at least two of these, further containing at leastone element selected from Ag, Au, B, C, Cr, Mo, Mn, P, S, Si, Pb, Pd,Rh, Ru, Sn, V, W, and Zn; (iv) any of (i), (ii) or (iii) where saidmetallic coating also contains particulate additions in the volumefraction between 0 and 95% by volume.
 3. An article according to claim2, wherein the metallic coating contains particulate addition and saidparticulate addition is of one or more materials which is a metalselected from the group consisting of Ag, Al, Cu, In, Mg, Si, Sn, Pt,Ti, V, W, Zn; a metal oxide selected from the group consisting of Ag₂O,Al₂O₃, SiO₂, SnO₂, TiO₂, ZnO; a carbide of B, Cr, Bi, Si, W; carbonincluding carbon nanotubes, diamond, graphite, graphite fibers; ceramic,glass; and polymer material including PTFE, PVC, PE, PP, ABS, epoxyresin.
 4. An article according to any one of claims 1 to 3 containing apermanent substrate selected from the group of metals, metal alloys,glass, ceramics, filled polymeric materials and composites, carbon basedmaterials selected from the group of graphite, graphite fibers andcarbon nanotubes.
 5. An article according to claim 1 wherein saidfine-grained metallic layer is deposited by electrodeposition, physicalvapor deposition (PVD), chemical vapor deposition (CVD) and coldspraying techniques including kinetic metallization.
 6. An articleaccording to claim 1 wherein said fine-grained metallic coating has ahardness between 200 and 2,000 VHN and a yield strength of at least 300MPa.
 7. An article according to claim 1 containing an intermediateconductive layer between said metallic material and said substrate. 8.An article according to claim 7 where the intermediate conductive layercomprises a metallic layer constituted of Ag, Ni or Cu or a combinationof any two or all of these, and where the intermediate conductive layeris deposited by electroless deposition, sputtering, thermal spraying,chemical vapor deposition, physical vapor deposition or by any two ormore of these.
 9. An article according to claim 7 where the intermediateconductive layer comprises polymeric material with conductiveparticulates therein.
 10. An article according to claim 9 where theintermediate conductive layer is a conductive paint or a conductiveepoxy.
 11. An article according to claim 9 where the conductiveparticulates are composed of or contain Ag, Ni or Cu or graphite orother conductive carbon or a combination of two or more thereof.
 12. Anarticle according to claim 1, wherein said article is a component orpart of an automotive, aerospace, sporting equipment, manufacturing orindustry application.
 13. An article according to claim 12 selected fromthe group consisting of golf clubs, fishing rods, arrows, hockey sticks,baseball/softball bats, tennis racquets, lacrosse sticks, ski poles,walking sticks, skate blades, snowboards, bicycle frames and molds. 14.An article according to claim 1, wherein said article has a tubularstructure and said fine-grained metallic material extends over at leastpart of the inner or outer surface of said tubular structure.
 15. Anarticle according to claim 14 selected from the group of golf clubshaft, arrow shaft, cartridge casing, baseball/softball bat, fishingrod, ski and hiking poles and bicycle parts.
 16. An article according toclaim 14 wherein said article comprises a substrate made of acarbon-containing material selected from the group of glass fibers,graphite, graphite fibers, carbon, carbon fibers and carbon nanotubes.17. An article according to claim 14, having a fine-grained metalliccoating with a hardness of greater than 500 VHN and a ratio of wallthickness to grain size of greater than 1,000.
 18. An article accordingto claim 14, wherein said article is wire or cable and said fine-grainedmetal, metal alloy or metal matrix composite coating represents between5 and 95% of the total weight of said article.
 19. An article accordingto claim 1 having an fine-grained metallic material coating on asubstrate containing graphite/carbon fibers embedded in epoxy, whereinthe weight of the fine-grained metallic material is between 5 and 95% ofthe total weight of the article.
 20. An article according to claim 1,wherein said fine-grained metallic material is a Ni, Co or Fe basedalloy and the substrate contains graphite/carbon fibers embedded inepoxy.
 21. An article according to claim 19 or 20, wherein said articleis a golf club shaft, arrow shaft, cartridge casing, baseball/softballbat, fishing rod, ski and hiking poles; a mold, mold component ortooling part; or an automotive or bicycle part.